Variability of the response to high and low temperatures of germination in Lycopersicon sp.

Seed of Lycopersicon esculentum, L. pimpinellifolium, L. hirsutum,and L. glandulosum stocks were germinated in temperatures of 5, 8, 10 and 25 C. In all L. esculentum and L. pimpinellifolium cultivars and lines the best and fastest germination was observed at temperatures of 25 C and in most cases it was completed in two weeks. For these stocks, the lower the temperature, the poorer seed germination.

Different response to low and high temperatures was observed in L. hirsutum and L. glandulosum accessions originating from high altitudes.

Among all accessions tested, the best germination at low temperatures was observed in L. glandulosum (PI 126444). For this accession there was only a slight delay in germination at low temperatures.

Unusual responses to low (10 C) and high (25 C) temperatures were found in three L. hirsutum accessions, (PI 127827, LA 386 and LA 1777) which germinated better at low than at high temperatures (Table 1). For other L. hirsutum stocks the germination was slower in low than in high temperatures and the percentage of germinating seed was lower or similar.

Some seeds which failed to germinate at 25 C after thirty three days subsequently germinated at temperatures about 12 C.

These findings indicate great variability in Lycopersicon stocks in germination response to low and high temperatures. Variability within some accessions may also exist for germination response to low temperature.

Table 1. Percentage of germination.

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                                                 1982     1983
                                               10C 25C  10C 25C
                                      Altitude  days     days
Species,   accession  Place of Origin (meters)15 61 14 15  53 14
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L.hirsutum *PI 127827 Cajamarca,Peru     3000          90 100 28
           *LA    386 Cajamarca,Peru     3000  8 52  7 94  99 75
           *LA   1777 Rio  Casma,Peru    3200          53  87 55
            LA   1557 Huaral-Cerro   2500-3000 1 36 42
                      de Pasco,Peru
            No. 1        unknown               2 26 33
            PI 390659 Huacabamba Peru    2300  0 38 86 30  49 55
           *PI 390663 Huacabamba,Peru          1 18 78
            PI 390513 Colca/Loja,Equador 2700  1  8 57 46  60 99
           *PI 390658 Canchaque, Peru     700           4  15 66

L.glandulosum 
           *Pl 126444 West of            2700          95  95 92
                      Rio Canta,Peru
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